A method for detecting the load of an internal combustion engine is described in German Patent Application No. DE 197 50 191 in which a first measure for the air mass flow supplied to the engine is measured, while a second measure is determined indirectly from the position of a throttle valve. A diagnostic method pinpoints an error when the two measures deviate from one another to an inadmissible degree.
A method and a device for checking the position of an actuator for a motor vehicle are described in German Patent Application No. DE 199 58 394. An image processing system determines the image provided by a camera and determines the position of the actuator, which in this case is a throttle valve of an internal combustion engine. The method provides an error signal when the angle position of the throttle valve deviates from a predefined setpoint value.
A method for operating an internal combustion engine is described in German Patent No. DE 199 06 287, a particulate filter being situated in the engine's exhaust duct. The load condition of the particulate filter is detected by a pressure sensor which determines the differential pressure occurring at the particulate filter, the differential pressure being a performance characteristic of the particulate filter. Subsequent to the request for regenerating the particulate filter, at least one measure is introduced, resulting in heating of the particulate filter. An increase in the exhaust gas temperature is provided. Moreover, a temperature sensor may be provided which determines the temperature at or in the particulate filter as another performance characteristic of the particulate filter.
A method for controlling the secondary air supply for an internal combustion engine is described in German Patent No. DE 43 09 854 in which a secondary air pump is provided for adding fresh air to the exhaust gas of the internal combustion engine, the secondary air pump being switchable in its performance. Subsequent to the request for heating a catalytic converter situated in the exhaust duct of the engine, the secondary air pump is put into operation. The added fresh air may exothermally react with combustible components of the exhaust gas and may thus contribute to heating of the exhaust gas and/or of a catalytic converter situated in the exhaust duct.
A method for desulfurizing a storage catalytic converter is described in German Patent Application No. DE 100 05 954 in which, subsequent to a request, the catalytic converter is heated due to the fact that combustible exhaust gas components and oxygen are moved downstream from the catalytic converter, either simultaneously or in alternating rapid succession, and react exothermally either downstream from or in the catalytic converter.